Methods and systems for masking multimedia data

ABSTRACT

Several methods and systems for masking multimedia data are disclosed. In an embodiment, a method for masking includes performing a prediction for at least one multimedia data block based on a prediction mode of a plurality of prediction modes. The at least one multimedia data block is associated with a region of interest (ROI). A residual multimedia data associated with the at least one multimedia data block is generated based on the prediction. A quantization of the residual multimedia data is performed based on a quantization parameter (QP) value. The QP value is variable such that varying the QP value controls a degree of masking of the ROI.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/417,896 filed Mar. 12, 2012, which application claims the benefit ofIndian Provisional Patent Application No. 835/CHE/2011, filed in theIndian Patent Office on Mar. 18, 2011, both of which are incorporatedherein by reference in their entirety.

TECHNICAL FIELD

The present disclosure generally relates to masking multimedia data.

BACKGROUND

The sharing of multimedia content has become rather important in modernhuman societies. However, with an extensive utilization of multimediatechnology in various spheres of life, various privacy issues associatedwith multimedia content have also gained importance. In an exemplaryscenario, “privacy masking” is used to mask private regions ofmultimedia content (for example, video content) so that the given regionwill not be revealed. For example, while interviewing someone who doesnot want her identity to be revealed, the face of the interviewee may bemasked by utilizing privacy masking. As another example, whileperforming surveillance of a street, windows of adjoining houses may bemasked so as to maintain or protect a level of privacy for these housesand their occupants.

SUMMARY

Various methods and systems for masking multimedia data are disclosed.In various embodiments, the masking of multimedia data may be performedfor the purpose of maintaining privacy. In an embodiment, a computerimplemented method of masking multimedia data includes performing aprediction for at least one multimedia data block based on a predictionmode of a plurality of prediction modes. The at least one multimediadata block is associated with a region of interest (ROI). A residualmultimedia data associated with the at least one multimedia data blockis generated based on the prediction. The method also includesperforming a quantization of the residual based on a quantizationparameter (QP) value. The QP value is variable such that varying the QOvalue controls a degree of masking of the ROI.

In one embodiment, a system for masking multimedia data is provided. Thesystem includes a prediction module and a quantization module. Theprediction module is configured to perform a prediction for at least onemultimedia data block based on a prediction mode of a plurality ofprediction modes. The at least one multimedia data block is associatedwith a ROI. The prediction module is further configured to generate aresidual multimedia data associated with the at least one multimediadata block based on the prediction. The quantization module iscommunicatively associated with the prediction module. The quantizationmodule is configured to perform a quantization of the residual based ona QP value. The QP value is variable such that varying the QP valuecontrols a degree of masking of the region of interest.

Moreover, in an embodiment, an integrated circuit for masking ofmultimedia data is provided. The integrated circuit comprises atransceiver module, a multimedia processing module and a memory module.The transceiver module is communicatively associated with a plurality ofmultimedia resources and is configured to receive multimedia data from amultimedia resource. The multimedia processing module is communicativelyassociated with the transceiver module and is configured to performmasking of the multimedia data. The multimedia processing modulecomprises a prediction module and a quantization module. The predictionmodule is configured to perform a prediction for at least one multimediadata block based on a prediction mode of a plurality of predictionmodes. The at least one multimedia data block is associated with a ROI.The prediction module is further configured to generate a residualmultimedia data associated with the at least one multimedia data blockbased on the prediction. The quantization module is communicativelyassociated with the prediction module. The quantization module isconfigured to perform a quantization of the residual based on a QPvalue. The QP value is variable such that varying the QP value controlsa degree of masking of the ROI. The memory module is communicativelyassociated with the transceiver module and the multimedia processingmodule, and is configured to store the multimedia data subsequent to themasking of the multimedia data.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a simplified overview of facilitating a masking ofmultimedia data in accordance with an exemplary scenario;

FIGS. 2A and 2B illustrate an exemplary implementation for facilitatinga masking by utilizing various values of QP for multimedia data inaccordance with an exemplary scenario;

FIG. 3 illustrates a process flow implementation for facilitating amasking of multimedia data in accordance with an embodiment;

FIG. 4 illustrates a system for facilitating a masking of multimediadata in accordance with an embodiment;

FIG. 5 illustrates a variation of values of QP for ROI against anaverage QP value for a current frame of multimedia data in accordancewith an embodiment;

FIGS. 6A through 6C illustrate multimedia data being masked inaccordance with an exemplary embodiment;

FIG. 7 illustrates an H.264 frame being masked in accordance with anembodiment;

FIG. 8 illustrates an exemplary implementation of at least one guardband in a H.264 intra frame in accordance with an exemplary embodiment;

FIG. 9 illustrates a masking in an intra-frame (e.g., an MPEG4 frame) inaccordance with an embodiment;

FIGS. 10A, 10B, 10C and 10D illustrate various stages of masking forinter-predicted frames in accordance with an exemplary embodiment;

FIGS. 11A and 11B illustrate a masking for multimedia data associatedwith a high degree of motion in accordance with an embodiment;

FIG. 12 is a flow diagram of a method of masking multimedia data inaccordance with an embodiment; and

FIG. 13 is a block diagram of an integrated circuit for masking ofmultimedia data in accordance with an embodiment.

DETAILED DESCRIPTION

The following description and accompanying figures demonstrate that thepresent technology may be practiced or otherwise implemented in avariety of different embodiments. It should be noted, however, that thescope of the present technology is not limited to any or all of theembodiments disclosed herein. Indeed, one or more of the devices,features, operations, processes, characteristics, or other qualities ofa disclosed embodiment may be removed, replaced, supplemented, orchanged.

Pursuant to an exemplary scenario, a privacy masking technique isperformed by processing multimedia data prior to encoding the videocontent. An exemplary embodiment explaining the preprocessing of themultimedia data for privacy masking is described herein with referenceto FIG. 1.

FIG. 1 illustrates a simplified overview 100 of facilitating a maskingof multimedia data in accordance with an exemplary scenario. Inparticular, the multimedia data may be captured at 102, such as by amultimedia capture device (e.g., a video capture device). An example ofmultimedia data may include, but is not limited to, video data capturedby the video capture device. Examples of a video capture device mayinclude a video camera or a camcorder. The video capture device may be,for example, a stand-alone device or a part of a mobile device, such asa Smartphone, or a data processing device, such as a personal computer,a laptop device or a personal digital assistant (PDA).

At 104, a preprocessing of the captured multimedia data is performed forprivacy masking. In an exemplary embodiment, preprocessing of themultimedia data overwrites the portions of the multimedia data that areto be masked. In an embodiment, the portions of the multimedia data aremasked with gray colored pixels. In one exemplary embodiment, thepreprocessing comprises an image subtraction for masking the portions ofthe multimedia data. In particular, image subtraction includessubtracting the portions of the multimedia data that are to be masked byutilizing a fixed pattern image. In one exemplary embodiment, thepreprocessing is performed by utilizing additional hardware/software toattenuate image details in the portions of the multimedia data. In anembodiment, various software preprocessing algorithms utilized toattenuate the details are configured to smooth or smudge the maskedportions of the multimedia data (either in a spatial domain or afrequency domain).

Pursuant to an exemplary scenario, after the preprocessing, an encodingof the preprocessed multimedia data is performed at 106 to achieve thecompression of the multimedia data. The multimedia data is to becompressed so as to efficiently utilize storage capacity during storage,or, to efficiently utilize spectrum/bandwidth during a transmission. Amultimedia encoder may be configured within a multimedia system toencode the multimedia data. Examples of the multimedia system mayinclude, but are not limited to: multimedia devices, such as cellularphones, digital video cameras and digital camcorders; data processingdevices, such as personal computers, laptops and personal digitalassistants; and consumer electronics, such as set top boxes, digitalvideo disk (DVD) players and video network servers.

In an exemplary scenario, the multimedia encoder may be any machinecapable of executing a set of instructions (sequential and/or otherwise)so as to perform an encoding of multimedia data. In an embodiment, themultimedia encoder is programmed to comply with a video compressionstandard. Examples of the video compression standards include, but arenot limited to, video coding experts group (VCEG), H.120, H.261, movingpictures experts group (MPEG), MPEG-1 Part 2, H.262 or MPEG-2 Part 2,H.263, MPEG-4 Part 2, H.264 or MPEG-4 AVC, VC-2 (Dirac), high efficiencyvideo coding (HEVC), and the like.

In an embodiment, the multimedia encoder receives preprocessedmultimedia data. Pursuant to an exemplary scenario, the multimedia datamay include a plurality of frames, and each frame from among theplurality of frames may include several blocks of multimedia data. Themultimedia encoder determines a prediction for each block of multimediadata, and therefrom subtracts the corresponding original block ofmultimedia data to form residual multimedia data (or a residual). Theprediction for each block of multimedia data may be performed based onpreviously encoded blocks of multimedia data, either from a currentframe (e.g., intra-prediction) or from other frames that have beenalready been encoded and transmitted (e.g., inter-prediction).Identifying a suitable inter-prediction may be referred to as ‘motionestimation’, and subtracting the inter-prediction from the current blockmay be referred to as ‘motion compensation’.

After prediction and subtraction, the residual multimedia data istransformed and quantized. The transformation of the residual multimediadata outputs a set of transform coefficients, each of which is aweighting value for an exemplary basis pattern. The weighted basispatterns, when combined, are capable of re-creating the residualmultimedia data. The set of transform coefficients are then quantized byutilizing a quantization parameter (QP). In particular, each coefficientis divided by an integer value, which may be referred to as a scalingfactor, thus effectively setting a number of transform coefficients to azero value, so as to achieve compression.

The quantized transform coefficients, along with certain information(such as, for example, information about the structure of compresseddata, information about a complete sequence of multimedia data and/orinformation that enables a decoder to re-create the prediction) areentropy encoded (e.g., converted into binary codes using variable lengthcoding and/or arithmetic coding). The entropy encoding of the multimediadata produces an efficient, compact binary representation of theinformation in the form of encoded multimedia data. The encodedmultimedia data may then be stored and/or transmitted.

At 108, the encoded multimedia data is decoded in order to achieve thedecompression of the multimedia data. In an embodiment, the decoding ofthe encoded multimedia data may be performed by a decoder, such as amultimedia decoder. The multimedia decoder is configured within amultimedia system. In various embodiments, the multimedia data isdecoded into the original multimedia data, or similar to the originalframe, depending on the lossy/lossless compression technique that isimplemented. In the multimedia decoder, the encoded multimedia data maybe entropy decoded (e.g., converted from the binary form, first intointermediate symbols and thereafter into quantized transformcoefficients) along with decoding of other encoded information. Thequantized transform coefficients may be de-quantized (e.g. multiplied bythe scaling factor and then inversely transformed) to obtain theresidual multimedia data. The residual multimedia data may then be added(e.g. combined with predicted blocks configured from the otherinformation decoded along with the quantized transform coefficients) tore-create the blocks of multimedia data. After the decoding, such as,for example, at 110, the decoded multimedia data may be displayed in adisplay device. Examples of the display device include, but are notlimited to, a liquid crystal display (LCD). In an exemplary embodiment,the display device may be configured inside the system for privacymasking. Pursuant to one embodiment, however, the display device may beconfigured external to said system.

Pursuant to the above example, the preprocessing of the multimedia datais explained by various techniques, such as, for example, by graying thepixels of the portion of the multimedia content to be masked, bysubtracting the portion in question from a fixed pattern image, byutilizing additional hardware/software, and the like. However, the abovemethods of privacy masking may have one or more disadvantages. Forexample, some of these methods include extra computation and/or thetransfer of multimedia data to perform privacy masking, which canthereby degrade the performance of the multimedia solution. As a result,if the performance of a solution is to be increased, the cost of thesolution will consequently increase. In some of the embodiments, whereinadditional hardware is utilized for implementing privacy masking, thesilicon area of the device incorporating the privacy masking system isincreased, thereby increasing the overall cost. Additionally, it may bedifficult to implement the preprocessing mechanisms in the existingdevices that are devoid of in-built support for privacy maskingsolutions. Further, in various solutions, the portions of the multimediadata to be masked are completely replaced by another pattern, therebyleading to the substantial obscuring of the underlying objects. Suchresults may not be desirable in scenarios where the primary objective isto partially obscure the details of the objects/person in the multimediadata. For example, in the masking of a keypad in an ATM machine, it maybe beneficial to obscure the key combinations that a user is inputting,although it may also be beneficial to nevertheless know whether the useris accessing the keypad or not. Thus, it may be beneficial to be able tocontrol a degree of privacy.

In various other scenarios, due to the preprocessing of the multimediadata, an additional processing and Direct Memory Access (DMA) bandwidthare required, which thereby results in greater system cost and reducedperformance. Preprocessing may also increase the end to end systemlatencies.

Various embodiments of the present technology, however, provide methodsand systems for facilitating a masking at a region of interest (ROI) ina simple and effective manner by precluding (or enabling one to avoid)complex preprocessing techniques without incurring additional cost withrespect to the hardware. For example, in an embodiment, the masking inthe multimedia data may be provided by performing a prediction based ona worst prediction mode, thereby resulting in a substantially highresidual multimedia data. This high residual multimedia data maythereafter be coded with a high value of the QP, thereby obscuring thedetails of the multimedia data. In various embodiments, the QP value maybe varied so as to achieve a varying degree of masking of the multimediadata. An exemplary implementation of facilitating a masking in themultimedia data is illustrated in FIGS. 2A and 2B.

FIGS. 2A and 2B illustrate an exemplary implementation for facilitatinga masking by utilizing various values of QP for multimedia data (e.g.,for an image frame). In the exemplary embodiment illustrated in FIG. 2A,a frame 210 comprises a human face region 212, wherein the face region212 is masked by utilizing a high QP value in the region 212. The maskedface region is marked as 214. FIG. 2A also illustrates a multimedia datablock view 220 of the frame 210. The multimedia data block view 220 isshown to include multimedia data blocks corresponding to the contents ofthe frame 210. For example, corresponding to the masked face region 212,the multimedia data block view 220 includes, for example multimedia datablock 224, 226 enclosed within a region 228. In various embodiments, theface region that is to be masked may be referred to as a region ofinterest (ROI). For example, the ROI is illustrated as 212 and 228 inFIG. 2A.

In an embodiment, the blocks, such as blocks 224, 226, associated withthe ROI 220 can be inter-predicted by utilizing a high QP value toperform a masking of the associated face portion 212. However, if theprediction in the ROI 212/228 is performed by utilizing an efficientprediction mode, the blocks (for example, 224, 226) lying at the ROI212/228 will be inter-predicted properly, and, accordingly, apreselected level of privacy masking is not achieved in the face regioncorresponding these blocks. In an embodiment, such blocks may have beeninter-predicted as ‘skip-blocks’ by an encoder. The skip-blocks areillustrated in FIGS. 2A and 2B.

For example, and with reference to FIG. 2B, an image frame 230 isillustrated with a corresponding multimedia data block view 240. Theframe 230 comprises a face portion, for example, the face portion 232.The face portion 232 is shown to be masked in a masked region 234, andthe corresponding portion in the multimedia data block view 240 ismarked as 242. The masked region 242 is shown to include multimedia datablocks, such as 244, 246.

In an example embodiment, a portion 236 of the privacy masked region 234remains unmasked, since the blocks, associated with said region werecoded as skip-blocks. It is noted that, when the prediction in a regionof a frame is good, the associated blocks are coded without sending aresidual error or motion vectors, and the encoder records such blocks asskip-blocks. Also, a multimedia decoder may deduce the motion vector ofthe skip-block from the block that has already been decoded. As theblocks 244, 246 associated with the region 242 are coded as skip-blocks,there is no residual multimedia data is left, and merely increasing QPdoes not have an effect, which renders the ROI unaffected by the privacymasking.

With reference still to FIG. 2B, the frame 230 comprising the faceregion may include skip-blocks (such as blocks 244, 246),intra-predicted blocks (for example, blocks 248, 250), andinter-predicted block (for example, blocks 252, 254). In someembodiments, the blocks (for example the blocks 248, 250) that areplaced adjacent to the ROI 242 are coded as intra-predicted blocks. Suchblocks produce a spilling noise, thereby distorting the adjoining image.The phenomenon of the spilling noise is explained in more detail hereinwith reference to FIG. 7.

In the embodiments illustrated in FIGS. 2A and 2B, when the masking isperformed by merely increasing the QP value of the multimedia dataassociated with the ROI, the prediction may be good, and, hence, thepreselected level of privacy masking may not be achieved. Accordingly,it may be beneficial to perform the masking in a manner such that asuitable level of masking is achieved. In various embodiments, a morerobust way of achieving a beneficial level of masking is to firstperform a prediction based on a worst prediction mode, therebygenerating a high residual multimedia data and enabling a better maskingof the multimedia data to be achieved.

FIG. 3 illustrates a process flow implementation for facilitating amasking of multimedia data in accordance with an embodiment. Examples ofmultimedia data may include video data, image data, audio-video data andthe like. In particular, blocks 302, 306, and 308 outline an exemplaryprocess implementation for the capturing, decoding and displaying,respectively, of multimedia data, whereas block 304 outlines variationsin a process implementation for the encoding of multimedia data. Forexample, at 302 of the masking process flow 300, multimedia data iscaptured by a multimedia capturing device, such as, for example,cellular phones, digital video cameras, digital camcorders, and thelike.

The captured multimedia data is thereafter encoded at 304 in a mannerthat at least one portion of multimedia data is masked. In anembodiment, this aforementioned “at least a portion” is the ROI of themultimedia data, and comprises at least one multimedia data block. Invarious embodiments, the ROI may be masked based on a prediction modethat is configured to provide a worst prediction, thereby outputtingsubstantially high residual multimedia data or residual energy. Aquantization of the resultant/residual energy with a QP of high value isperformed, thereby masking the information associated with the at leastone portion of the multimedia data. In various embodiments, the QP valuemay be varied so as to control a degree of masking of the ROI. Afterencoding, at 306, the encoded multimedia data may be decoded anddecompressed by, for example, a multimedia decoder. At 308, the decodedmultimedia data may be displayed, such as using an exemplary processimplementation for displaying multimedia data.

The disclosed process flow 300 provides solutions for the effectivemasking of multimedia data. However, in some embodiments, masking of themultimedia data may result in the production of a spilling noise. In amasked image frame, the spilling noise is represented by distortion ofthe regions adjacent to the ROI, which is a scenario that may bebeneficial to avoid. Various embodiments provide solutions for privacymasking of the multimedia data without producing spilling effects. Forexample, in various embodiments, at least one guard band is provided inproximity to at least one boundary portion of the ROI. The at least oneguard band is configured to prevent a spilling of the masking to theneighboring regions of the ROI. In some embodiments, for example, incase of intra-predicted frames, the at least one guard band may includea single guard band. In some embodiments, for example, in case ofinter-predicted frames, the at least one guard band may include multipleguard bands. The concept of spilling noise and the guard bands isexplained herein in more detail. Various embodiments of the presentdisclosure are further disclosed herein with reference to FIGS. 4 to 8.

FIG. 4 illustrates a system 400 for facilitating a masking of multimediadata (e.g., multimedia data 402) in accordance with an embodiment.Examples of multimedia data may include video data, image data,audio-video data and the like. In an embodiment, the system 400 may be amultimedia encoder. In one embodiment, the system 400 is a highefficiency video coding (HEVC) based video encoder. In one embodiment,the system 400 is (or includes) a moving pictures expert group (MPEG)-1based video encoder, MPEG-2 based video encoder and/or MPEG-4 basedvideo encoder. In an embodiment, the system 400 may be a stand-alonedevice or configured within a multimedia system. Examples of themultimedia systems may include, but are not limited to: multimediadevices, such as cellular phones, digital video cameras and digitalcamcorders; data processing devices, such as personal computers, laptopsand personal digital assistants; and consumer electronics, such as settop boxes, digital video disk (DVD) players and video network servers.

In various embodiments, in order to perform a masking of at least aportion of the multimedia data, the at least one multimedia data blockassociated with at least the portion of the multimedia data ispredicted. In various embodiments, the masking of the ROI is achieved byreducing the prediction effectiveness at the ROI, and, hence, increasingthe residual energy. The at least one multimedia data block is predictedbased on the DC prediction mode so as to generate predicted multimediadata blocks. The predicted multimedia data blocks are subtracted fromthe corresponding at least one multimedia data blocks to therebygenerate residual multimedia data blocks of high residual energy. Anincrease in the residual energy facilitates a masking of the details ofthe multimedia data at the ROI.

The system 400 is depicted to include a prediction module 404, aquantization module 406, and an entropy encoding module 408. In variousembodiments, the system 400 may also include a prediction modedetermination module 410, a guard band determination module 412, a QPdetermination module 414, and a rate control module 416.

The prediction module 404 is configured to perform a prediction for atleast one block of multimedia data. The at least one block of multimediadata is associated with the ROI. In various embodiments, the predictionfor the at least one block of multimedia data 402 may be determinedbased on previously encoded blocks of multimedia data 402, either from acurrent frame (e.g., intra-prediction) or from other frames that havebeen already been encoded and transmitted (e.g., inter-prediction). Inan embodiment, the prediction module 404 includes an inter-predictionmodule 418 and an intra-prediction module 420. The inter-predictionmodule 418 is configured to perform an inter-prediction of the at leastone block of the multimedia data, while the intra-prediction module 418is configured to perform an intra-prediction of the at least one blockof the multimedia data. Various embodiments that include the masking ofintra-predicted and inter-predicted multimedia data are explained hereinin detail.

In various embodiments, the prediction module 404 is further configuredto determine a residual multimedia data of the predicted multimedia datablock and a corresponding original multimedia data block. In anembodiment, the prediction for the at least one block of the multimediadata is determined based on the prediction mode.

In various embodiments, the prediction mode determination module 410 iscommunicatively associated with the prediction module 404, and isconfigured to determine the prediction mode suitable to perform amasking of the multimedia data. In various embodiments, the predictionmode determination module 410 is configured to select the mode from theplurality of prediction modes. For example for performingintra-prediction, the prediction mode determination module 410determines a plurality of values of SAD associated with the plurality ofprediction modes. The prediction mode determination module 410 selectsthe mode from the plurality of modes based on the determined pluralityof values of SAD. Particularly, the prediction mode determination module410 selects the mode having a highest value of SAD, since the highestvalue of SAD is associated with worst prediction, and thereby adequatemasking.

In various exemplary embodiments, the prediction mode determinationmodule 410 is configured to select a DC mode for performing theprediction. In an embodiment, selecting the DC mode for performing theprediction facilitates in avoiding the computation required incalculating the plurality of values of SAD for the plurality of modes,thereby saving computation effort and processing time of the system.

In various embodiments, for example for inter-prediction, the predictionmode determination module 410 is configured to determine the predictionmode for the at least one multimedia data block. In the presentembodiment, the prediction mode is determined by determining at leastone motion vector (MV) between a reference frame and at least onemasking frame of multimedia data. In an embodiment, the at least onemasking frame includes the at least one multimedia data block. In anembodiment, at least one corner pixel associated with the referenceframe is rendered grey, and a padding is performed for generating atleast one padded portion in the reference frame. In an embodiment, thepadding performed by using the at least one grey corner pixels resultsin generation of at least one grey corner portion. The at least one MVis caused to point towards the at least one grey corner portion torender the ROI grey. In the present embodiment, causing the at least oneMV to point towards the at least one grey corner portion provides a highresidual energy. The high residual energy is associated with a poorprediction, and thereby effective masking.

In various other embodiments, the prediction mode determination module410 is further configured to determine various other prediction modesassociated with the regions occupied by the at least one guard band. Theprediction modes for the regions occupied by the guard bands will beexplained later.

The guard band determination module 412 is communicatively associatedwith the prediction module 404, and is configured to determine at leastone guard band in proximity to at least one boundary portion of the ROI.In various embodiments, the at least one guard band is configured toprevent a spilling of the masking outside of the ROI. For example, theguard band determination module 412 may determine or select a guard bandtowards a right-side boundary portion of the ROI and another guard bandtowards a bottom boundary portion of the ROI.

In an embodiment, the guard band determination module 412 iscommunicatively associated with the prediction mode determination module410. In an exemplary embodiment, the prediction mode determinationmodule 410 is further configured to determine a vertical prediction modeto perform a prediction in the at least one guard band at the right-sideboundary portion of the ROI. In one exemplary embodiment, the predictionmode determination module 410 is configured to determine a verticalprediction mode so as to determine a horizontal prediction mode in orderto perform the prediction in the at least one guard band at thebottom-side boundary portion of the ROI.

The quantization module 406 is communicatively associated with theprediction module 404, and is configured to transform and quantize theresidual multimedia data output from the prediction module 404. Invarious embodiments, during quantization, the residual multimedia datais coded with a high QP value, thereby causing a reduction in thedetails of the object at the ROI by obscuring the information pertainingto such details.

In an embodiment, the quantization module 406 is also configured toreceive an input from the QP determination module 414. The QPdetermination module 414 is configured to determine a variable QP valuebased on a degree of masking desired for the multimedia data. In variousembodiments, the variable QP value may be based on a rate control. In anembodiment, the rate control may be determined by the rate controlmodule 416 that is coupled with or connected to the QP determinationmodule 414. In an embodiment, the rate control module 416 is configuredto output an average QP (QPf) value for a current frame of multimediadata and provide the same to the QP determination module 414.

In various embodiments, the QP determination module 414 determines theQP value to achieve different levels of masking. In an exemplaryembodiment, the QP determination module 414 determines the QP value(represented as QPpf) based on a piecewise linear equation which yieldsprocessing simplicity without impacting masking quality. In variousembodiments, the following may be utilized for deriving the QP for themasked region:QPpf=QPf+(PF*(QPmax−QPf)/n)

wherein,

QPpf is the QP of the privacy masked region,

QPf is the average QP for the current frame given by the Rate control,

PF is a privacy factor with a value from 1-n, wherein n is an integer,and

QPmax is the Max QP value to be used.

In an embodiment, the value of PF is based on the degree of masking tobe implemented. For example, for various degrees of masking, the valueof PF may be set in a range of 1-5.

In an embodiment, the bit consumption that changed in the ROI affectsthe overall bits consumed in the frame of the multimedia data. In anembodiment, the number of bits consumed in a previous frame is input tothe rate control module 416, and the QPf of the next frame is modulatedaccordingly. Hence, there is no bitrate deviation in long term. Avariation of QPpf (e.g., the QP value for ROI) against QPf (e.g., theaverage QP value for a current frame) is illustrated in FIG. 5.

FIG. 5 illustrates a variation of values of QPpf (QP for ROI,represented as 502) against the value of QPf (average QP value,represented as 504) for a current frame of multimedia data in accordancewith an embodiment. In particular, for a variation of a privacy factorfrom 1 to 5, the value of QPpf is increasing with an increasing value ofQPf until a threshold value of PF is reached. For example, in theillustrated variation, the maximum value of PF is 5. In an embodiment,at the maximum value of PF (for example, when the value of PF is 5), thevariation between QPpf and QPf is linear.

With reference again to FIG. 4, in various embodiments, the quantizationmodule 406 is configured to perform the transformation and quantizationof the residual received from the prediction module 404 based on thevariable QP received from the QP determination module 414. Inparticular, transformation of the residual multimedia data outputs a setof transform coefficients, each of which is a weighting value for anexemplary basis pattern. The weighted basis patterns, when combined, arecapable of re-creating the residual multimedia data. The set oftransform coefficients are then quantized (e.g., each coefficient isdivided by an integer value, which may be referred to as a scalingfactor), effectively setting a number of transform coefficients to azero value so as to achieve compression.

The entropy encoding module 408 is coupled with or connected to thequantization module 406, and is configured to convert the quantizedtransform coefficients, along with certain information (for example,information about the structure of compressed data, information about acomplete sequence of multimedia data 402 and/or information that enablesa decoder to re-create the prediction) into binary codes using variablelength coding and/or arithmetic coding. The entropy encoding of themultimedia data produces an efficient, compact, binary representation ofthe information in the form of encoded multimedia data 422. The encodedmultimedia data 422 may then be stored and/or transmitted.

The system for masking multimedia data as explained in FIG. 4 may beimplemented in a system without having an impact (or with relativelyminimal impact) on the encoding process flow. For example, in thepresent implementation, no preprocessing step is involved to mask theROI with a color, such as, for example, a gray color. Accordingly, anadditional data load from the DDR to either subtract or overwrite themasked region may be avoided, and, therefore, the DMA data throughputremains the same as during a normal encoding flow. Also, in so much asthe implementation of additional hardware for preprocessing may beavoided, the overall integration of the masking system is simple. Thissolution may utilize existing encoder modules/blocks to achieve privacymasking. Hence, it can be used in various existing hardware basedsolutions. Performing the privacy masking in a manner outlined in FIG. 4enables the implementation of additional hardware, and complexpre-proceeding computations, to be avoided, in addition to minimizingcost and saving/conserving memory in a system for facilitating a privacymasking of the multimedia data.

An exemplary scenario indicating exemplary results of privacy masking inaccordance with an embodiment are illustrated with reference to FIGS. 6athrough 6c . It is noted that, in an embodiment, the exemplary resultsof privacy masking obtained pursuant to an exemplary implementation mayprove to be very efficient.

FIGS. 6A through 6C illustrate certain exemplary multimedia data beingmasked in accordance with an exemplary embodiment. Particularly, FIG. 6Aillustrates a frame 610 comprising an exemplary face region, such as,for example, the face region 612, that is to be privacy masked. FIG. 6Billustrates the face region 612 being masked based on theintra-prediction. For example, the region labeled as 614 is the portionof the face region 612 that is masked based on the intra-prediction.FIG. 6C illustrates the face region 612 being masked based on theinter-prediction. For example, the region labeled as 616 is the portionof the face region 612 that is masked based on the inter-prediction. Themasked face regions of FIGS. 6B and 6C are obtained by predicting themultimedia data blocks based on the DC prediction mode and, thereafter,applying a high QP value to obscure the details of the ROI, such as, forexample, the face region 612.

In some embodiments, the multimedia data blocks are intra-predicted. Theprocess of masking in the intra-predicted multimedia data blockscomprises predicting a weak intra-prediction mode that may poorlypredict the multimedia data block. Selecting a weak intra-predictionmode facilitates a saving of the block level computation that wouldotherwise be performed when a mode with a maximum sum of absolutedifferences (SAD) is selected for intra-prediction. It is noted that SADmay be used to determine a motion estimation for video compression. Inparticular, SAD is indicative of a measure of the similarity betweenvarious blocks of multimedia data of a frame. The process implementationof SAD comprises determining an absolute difference between each pixelin the original block and the corresponding pixel in the block beingused for comparison. These differences are summed to create a simplemetric of block similarity.

In various embodiments, residual multimedia data blocks are computed bysubtracting the intra-predicted multimedia data blocks from the originalmultimedia data blocks and are thereafter coded using a variable (buthigher) QP value. Various multimedia standards, such as video codingstandards, may provide specifications for implementation of the systemfor privacy masking (as described in FIGS. 4 and 6A, 6B, 6C) byutilizing the DC mode of intra-prediction. Various implementations ofthe disclosed masking technique as proposed for the multimedia codingstandards, such as H.264 and MPEG4, is described in detail herein withreference to FIGS. 7 through 12.

FIG. 7 illustrates an H.264 frame 710 being masked in accordance with anembodiment. A masked region, for example, the region 712 is obtained byusing the DC mode of intra-prediction. As illustrated in FIG. 7,performing the disclosed masking in ROI by utilizing the DC mode ofintra-prediction causes a spill over prediction noise (represented bythe region marked as 714) to spread in the unmasked region (or outsideof the boundary of ROI). In order to avoid the spill-over to theunmasked regions, at least one guard band may be implemented.

In various embodiments, the at least one guard band is provided inproximity of at least one boundary portion of the ROI. The guard band isconfigured to contain the spilling effects of the DC mode to theun-masked region to thereby prevent the spilling of the masked image.The implementation of the guard band in the H.264 intra frame isexplained in detail herein with reference to FIG. 8.

FIG. 8 illustrates an exemplary implementation of at least one guardband in a H.264 intra frame in accordance with an exemplary embodiment.As illustrated in FIG. 8, an H-264 intra frame, such as, for example, aframe 810 may include a ROI, such as, for example, a region marked as812, that is to be masked. As explained herein with reference to FIG. 5,in the absence of a guard band, the privacy masking applied to theregion 812 may spill into the regions adjacent to the ROI, therebydistorting the regions lying adjacent to the ROI 812, which is ascenario that may be beneficial to avoid. As discussed herein, at leastone guard band is provided in at least one of the boundary regions ofthe ROI so that said spilling effect of the masked region can becontained.

As illustrated in FIG. 8, at least one guard band, such as, for example,a guard band 814 in a right-side portion, and a guard band 816 in thebottom portion, of the ROI 812 are provided. The region comprising theguard band 814 may be intra-predicted based on a vertical prediction,while the region comprising the guard band 816 may be predicted based ona horizontal prediction. The vertical prediction and the horizontalpredictions in the regions lying on the right side and bottom side,respectively, of the ROI 812 ensure that none of the blocks of themultimedia data lying outside the ROI have prediction pixels overlappingthereon. As discussed herein with reference to FIG. 4, the horizontalprojection and the vertical projection for the regions 814 and 816,respectively, may be determined by the prediction mode determinationmodule (for example, the prediction mode determination module 410). Itis noted that remainder of the region of the frame 810, for example, theregion marked as 820, may be processed based on the best mode ofintra-prediction with a minimum SAD.

In certain embodiments, the algorithmic implementation for performing amasking of an intra-predicted multimedia data block may be representedas follows:

if(Current multimedia data block is in ROI) {  Force intra-predictionmode as DC16x16 ( ); } else if(Current multimedia data block is inright-side guard band) {  Force Vertical Intra-prediction ( ); } elseif(Current multimedia data is in bottom guard band) {  Force HorizontalIntra-prediction ( ); } else {/*---------------------------------------------------*/ /*Normal Flow *//*Use the selected Best intra mode (min SAD)  *//*--------------------------------------------------*/ }

Still referring to FIG. 8, the at least one guard band forintra-prediction is shown and described to include two guard bands, forexample, the guard band 814 and the guard band 816. It will, however, beunderstood that in various embodiment, the at least one guard band mayinclude only one guard band, for example, the guard band 814 forpreventing said spilling instead of multiple guard bands.

In various embodiments, a width of the at least one guard band may beequal to one multimedia data block. In an embodiment, the multimediadata block may comprise a macro-block, for example, of 16×16 pixels, andaccordingly the width of the at least one guard band may be equal to 16pixels only. In various other embodiments, the width of the multimediadata block may be lesser or more than one multimedia data block. Forexample, in certain embodiments, the at least one guard band such as theguard band 814 may be a sub-macro block wide only, for example 4 pixelswide.

FIG. 9 illustrates a masking in an intra-predicted frame (e.g., an MPEG4frame) in accordance with an embodiment. In particular, in MPEG4standard, the intra-predicted multimedia data blocks are coded bydetermining a DC prediction and an AC prediction. The DC prediction inthe MPEG4 standard is ON (or activated) by default for all of the macroblocks, while the AC prediction can be enabled or disabled by theencoder. In various exemplary embodiments, the encoder enables ordisables the AC prediction by implementing an algorithm.

In various embodiments, in order to perform a privacy masking in theMPEG4 intra-predicted frame, an AC prediction may be switched OFF (ordeactivated) for ROI, thereby ensuring that the ROI has the worst caseprediction, such as, for example, the DC prediction. Unlike the H.264standard, in the event of an MPEG4 standard, forcing the usage of merelythe left multimedia data block, or merely the bottom multimedia datablock, for prediction may not be possible. Also, switching OFF ordeactivating the DC prediction for an intra-predicted multimedia datablock may not be possible. Accordingly, in the event of the MPEG4standard, the DC of the intra-predicted multimedia data block ispredicted from either the left-side multimedia data blocks or the topmultimedia data block DC values.

With reference still to FIG. 9, three neighboring multimedia datablocks, such as, for example, a block 902, a block 904 and a block 906,are illustrated. For a current multimedia data block 906, let us assumethat the residual energies of the multimedia data block 902, 904, 906are represented by blocks 908, 910, 912, respectively:

 Label 912 is indicative of the DC energy of the current  multimediadata block 906,  Label 908 is indicative of the DC energy of themultimedia  data block (block 902) appearing to the left of the currentmultimedia data block (block 906), and  Label 910 is indicative of theDC energy of multimedia  data block (block 904) appearing above thecurrent multimedia data block (block 906), then  if (abs(908-912) <abs(910-912))  {   DC of the current multimedia data block is predictedfrom the left  multimedia data block  }  else  {   DC of the currentmultimedia data block is predicted from the top  multimedia data block }

In an embodiment, the predicted multimedia data blocks are subtractedfrom the corresponding original multimedia data blocks to obtainrespective resultant or residual multimedia data blocks. A high QP valueis applied to the residual multimedia data blocks so as to obtainprivacy masking in the ROI. In the present embodiment, the QP of themultimedia data blocks associated with the masked region (or the ROI) ishigh, and, accordingly, the probability of selecting masked multimediadata blocks for DC prediction is much less, which thereby avoids thespilling effect. The privacy masking technique for the inter-predictedmultimedia data blocks is explained herein with reference to FIGS.10A-10D

FIGS. 10A, 10B, 10C and 10D illustrate various stages of masking forinter-predicted frames in accordance with an exemplary embodiment. Asillustrated in FIG. 10A, a frame 1002 is an inter-predicted frame. In anexemplary embodiment, the frame 1002 is assumed to include a faceportion, such as, for example, the face portion 1004, which needs to bemasked. Thus, the face portion 1004 is the ROI.

In order to perform a privacy masking, a prediction mode is determinedfor the inter-predicted frame 1002. In various embodiments, theprediction mode is determined to be a bad prediction mode that isconfigured to give a worst possible prediction in the ROI. In anembodiment, determining the prediction mode comprises pointing a motionvector (MV) towards a grey area in the image frame.

The inter-frame compression is performed by performing motion estimationbased prediction for the multimedia data blocks in a predicted framewith respect to a reference intra-coded frame and/or previously codedinter-frames. In various video standards, the motion estimation may beextended beyond a reference intra-coded frame region. In certain cases,the multimedia ‘content’ can be derived outside the frame region byrepeating the pixels of the edges of the frame so as to “fill” anextended region that may be used for motion estimation purposes. Forexample, as illustrated in FIG. 10B, the top row of the frame, such as,for example, the frame 1006, may be repeated in a vertical or upwarddirection, thereby expanding the image frame upwards so as to fill anextended motion estimation region below the picture. Likewise, thebottom row, the left and the right columns are repeated at the bottom,left and right sides, respectively, so as to provide extended motionestimation regions at those sides of the reference image frame. Thisprocess of filling areas outside of the original frame may be referredto as ‘padding’. Padding may be very useful for the objects which areentering and leaving the frame. The process of padding is performed invideo compression in order to improve the search.

In an embodiment, padding can be used to create a gray region in thereference frame without causing a substantial increase in data transferduring the process. This grey region can be utilized to perform aprediction during the masking process. In various embodiments, uponextending the edges of the frame 802 in all sides, the padded frame mayappear as illustrated in FIG. 10B.

With reference still to FIG. 10B, a padded image 1020 that is obtainedby padding the frame 1002 is illustrated. The padded region on all thefour sides are illustrated by means of margins, such as, for example,the margins 1006, 1008, 1010, 1012. In the padded regions, one or morecorners are made gray. For example, the pixels at a top left corner, atop right corner, a bottom left corner, and a bottom right corner,respectively, in the original image frame are converted to grey color.In an embodiment, when the reconstruction is proper, the pixelsassociated with these four corners remain grey.

When this image frame is padded, the grey pixels at one or more corners,such as, for example, the four corners, are expanded to make amultimedia data block lying outside of the boundary of the originalimage frame. For example, and with reference again to FIG. 8C, the fourcorners, such as the corners 1012, 1014, 1016 and 1018 are converted togrey. In various embodiments, each of the grey colored corner portionsin the padded region comprises a multimedia data block of grey color. Invarious embodiments, during inter-prediction, the motion vector isforced to point to the grey multimedia data blocks, such as atmultimedia data blocks 1012, 1014, 1016 and 1018 outside the frameboundary, thereby making the prediction image grey and hence yielding ahuge residual.

For example, referring to FIG. 10D, an exemplary image sequencecomprising various frames, such as, for example, a frame 1032, 1034,1036, and 1038, is shown. The frames comprise a portion that is desiredto be masked (for example, the ROI). For example, a frame 1034 comprisesa ROI, such as ROI 1042. Similarly, frames 1036 and 1038 comprise ROIs,such as ROI 1044 and 1046, respectively. In an embodiment, one of theframes from among the sequence of frames, such as, for example, theframe 1032, is a reference frame. As illustrated in FIG. 10D, thereference frame 1032 comprises an extended gray multimedia data block,such as, for example, the multimedia data block 1052. In variousexemplary embodiments, the MV associated with the ROI of one or moreother frames in the sequence points towards the grey multimedia datablock 1052 of the reference frame 1032. For example, a MV 1062 of theframe 1034 may point towards the grey multimedia data block 1052 of thereference frame, the MV 1064 of the frame 1036 may point towards thegrey multimedia data block 1054 of the frame 1034, and so on.

In certain video standards, a maximum length of a motion vector isspecified. Accordingly, in one embodiment, a grey colored multimediadata block is chosen, out of the four grey colored multimedia datablocks, that is closest to the ROI. In an embodiment, only the luminancepixels can be made as gray in order to generate a sufficient amount ofmasking. In certain other embodiments, chrominance pixels can also bemade gray in order to achieve a better degree of masking.

The masking technique for inter-predicted frames as disclosed herein maybe used in various video standards, such as, for example, H.264 videostandard, and MPEG4 video standard. The above process of privacy maskingenables additional complexity and cost in the design to be avoided, asthe padding is done automatically in the multimedia encoder and decodersuch that unrestricted motion vector support may be achieved.Accordingly, pursuant to one exemplary implementation, the graying ofthe corner multimedia data blocks in a reconstructed image incurs noadditional cost.

FIGS. 11A and 11B illustrate an exemplary masking for multimedia dataassociated with a high degree of motion in accordance with anembodiment. With reference to FIG. 11A, a frame 1102 comprising a sceneassociated with a high degree of motion is depicted. Particularly, thescene comprises a player playing a game. When the multimedia data, suchas, for example, the video content, comprises a high degree of motion,the un-masked region (for example, the region marked as 1104) can referto the masked region (for example, the region marked as 1106) of theprevious picture (e.g., the reference picture), and, accordingly, thereconstructed image for these multimedia data blocks in the currentframe may become distorted. For example, as illustrated in FIG. 11A, theportion 1104 of the image lying in close proximity to the ROI, such as,for example, the region 1102 is distorted due to the high degree ofmotion in the multimedia content.

In order to ensure a good quality reconstruction of the un-maskedregion, a mode decision of the region around the masked region may bebiased towards intra modes. In an embodiment, the mode decision aroundthe masked region may be biased by implementing ‘guard bands’ around themasked regions. The implementation of guard bands with respect to theinter-predicted frames is explained in detail with reference to FIG.11B.

Referring to FIG. 11B, an implementation of the at least one guard band,such as, for example, a guard band 1108 in an inter-predicted frame1110, is illustrated in accordance with an embodiment. In an embodiment,the inter-predicted frame 1110 comprises an area that is to be masked(e.g., a ROI), such as, for example, an area 1112. The area 1112 that isto be masked, or that is already masked, may be referred to as a maskedregion. In an embodiment, the at least one guard band 1102 may beprovided around the masked region 1112 in order to avoid the maskedregion 1112 to distort the picture clarity of the area in closeproximity thereof

In various embodiments, the distortion of the regions adjoining themasked area 1112 may be unnoticeable or insignificant, thereby enablingthe application of the guard band around the masked area to be avoided.Also, in such a scenario, the implementation of the guard bands may beconfigurable and selected based on the need of the applicationincorporating a privacy masking. For example, the at least one guardband 1108 may include four guard bands, each adjacent to one of the fourboundary regions of the masked region 1112. However, it will beunderstood that the at least one guard band may include one or more thanone guard bands, without limiting the scope of the present embodiment.

In various embodiments, a width of the guard band may be equal to onemultimedia data block. In an embodiment, the multimedia data block maycomprise a macro-block, for example, of 16×16 pixels, and accordinglythe width of guard band may be equal to 16 pixels only. In various otherembodiments, the width of the multimedia data block may be lesser ormore than one multimedia data block. For example, in certainembodiments, the guard band 1108 may be a sub-macro block wide only, forexample 4 pixels wide.

In an exemplary embodiment, an exemplary pseudo-code for determining theprediction with respect to inter-predicted frames may be implemented asfollows:

if(Current multimedia data block is in masked region) { ForceMVtoReferGrayRegion( ); } else if(IsIntraBiasIncluded) { CheckForGaurdBandRegionandBiasIntra( ); } else {/*--------------------------------------------------*/ /*Normal Flow *//*Use the selected Best inter mode (min SAD)  *//*--------------------------------------------------*/ }

FIG. 12 is a flow diagram of a method 1200 for masking multimedia dataaccording to an embodiment. The method 1200 starts at operation 1202. Atoperation 1202, a prediction for at least one multimedia data block isperformed. In an embodiment, the at least one multimedia data block isassociated with a ROI. In various embodiments, the prediction isperformed based on a prediction mode. In an embodiment, the predictionis performed based on DC prediction mode.

In various embodiments, at least one guard band can be determined inproximity to at least one boundary portion of the ROI. The at least oneguard band is configured to prevent a spilling of the masking toneighboring regions of the ROI (or outside the ROI boundary). Thedetermination of at least one of the guard bands for intra-predictedmultimedia data blocks and for inter-predicted multimedia data blockshave already been discussed herein with reference to FIGS. 8 and10A-10B, respectively.

In various embodiments, performing the prediction comprises performingthe prediction in the at least one guard band at a right-side boundaryportion of the ROI based on a vertical prediction mode, and performing aprediction in the at least one guard band at a bottom boundary portionof the ROI based on a horizontal prediction mode. As discussed hereinwith reference to FIG. 4, the prediction modes, such as, for example,the horizontal prediction mode and the vertical prediction mode aredetermined by the prediction mode determination module 410.

In accordance with certain embodiments, however, wherein the predictionis an inter-frame prediction, determining the inter-frame predictioncomprises predicting the at least one multimedia data block bydetermining at least one MV between a reference frame and at least onemasking frame. The at least one masking frame comprises the at least onemultimedia data block. The determination of the at least one MV betweenthe reference frame and the at least one masking frame is explainedherein with reference to FIG. 10D.

At operation 1204, a residual multimedia data is generated based on theprediction. In various embodiments, the residual multimedia data is adifferential of the original multimedia data and the predictedmultimedia data. Particularly, the residual multimedia data isindicative of a change in the content of the original multimedia dataand the predicted multimedia data. In various embodiments, the generatedresidual multimedia data is high for causing masking of the multimediadata associated with ROI.

In various embodiments, generating the residual multimedia datacomprises generating at least one padded portion in a reference frame,and creating at least one grey corner portion in the at least one paddedportion. The at least one MV is caused to point towards the at least onegrey corner portion to thereby render the ROI grey. The generation ofthe residual multimedia data by greying the corner portions of the atleast one padded portion is explained in detail with reference to FIGS.10A-10D.

At operation 1206, a quantization of the residual multimedia data isperformed based on a value of a QP. In an embodiment, the quantizationof the residual multimedia data is performed by the quantization module406 (see, e.g., FIG. 4). In various embodiments, the value of the QP isvariable such that a varying of the value of the QP controls a degree ofmasking of the ROI. In an embodiment, the variable values of QP may begenerated by QP determination module 414 (as explained herein withreference to FIG. 4) based on a rate control of the current frame. In anembodiment, the rate control may be determined by the rate controlmodule 416 (see, e.g., FIG. 4).

In an embodiment, the value of the QP is configured to control thedegree of masking of the ROI based on the following equation:QPpf=QPf+(PF*(QPmax−QPf)/n),

where

PF is a privacy factor associated with the degree of masking, andwherein the value of PF varies from 1-n,

QPf is an average QP value for a frame comprising the at least one MB,the value of QPf being determined by the Rate control,

QPpf is a value of QP at the ROI, and

QPmax is a maximum permissible value of the QP.

FIG. 13 is a block diagram of an integrated circuit 1302 for decodingand encoding multimedia data, according to an embodiment. The integratedcircuit 1302 comprises a transceiver module 1304, a multimediaprocessing module 1306, a memory module 1308 and a display module 1310.The transceiver module 1304, the multimedia processing module 1306, thememory module 1308 and the display module 1308 are communicativelyassociated with each other using data path 1312.

The transceiver module 1304 is communicatively associated with aplurality of multimedia resources 1314 and is configured to receivemultimedia data from a multimedia resource from among the plurality ofmultimedia resources 1314. Examples of the multimedia resources mayinclude, but are not limited to (1) remote multimedia systems, (2) mediacapture devices like surveillance camera, camcorders and the like, and(3) multimedia storage devices like magnetic tapes, disks, computerreadable media and the like. In an embodiment, the transceiver module1306 may include an antenna and/or network connectors to connect towired networks (for example, local area networks (LANs)) and wirelessnetworks (for example, cellular networks) or combination thereof (forexample, internet). Examples of network connectors may include auniversal serial bus (USB) interface, a wireless LAN interface, aninfrared interface, an Ethernet port and the like.

The multimedia processing module 1306 is configured to perform maskingof the multimedia data. In an embodiment, the transceiver module 1304 isconfigured to receive the multimedia data provide the multimedia data tothe multimedia processing module 1306. The multimedia processing module1306 is configured to facilitate masking of the multimedia data, andprovide the masked multimedia data to the memory module 1308 forstoring, or to the display module 1310 for displaying masked multimediamedia on the display 1316.

In an embodiment, the multimedia processing module 1306 may beconfigured to encode the multimedia data and provide the multimedia datato transceiver module 1304 for transmission purposes or to memory module1308 for storage purposes. In an embodiment, the multimedia processingmodule 1306 may be configured to include components of system 400explained in FIG. 4. For example, the multimedia processing module 1306may include components of system 400 such as the prediction module 404,the quantization module 406, the entropy encoding module 408, theprediction mode determination module 410, the guard band determinationmodule 412, the QP determination module 414, and the rate control module416. The components of the system 400 included in the multimediaprocessing module 1306 are not explained herein for sake of brevity.

The memory module 1308 is configured to store the multimedia datasubsequent to masking of the multimedia data. Examples of memory module1306 may include, but are not limited to, random access memory (RAM),dual port RAM, synchronous dynamic RAM (SDRAM), double data rate SDRAM(DDR SDRAM), and the like. The display module 1310 is configured tofacilitate display of the multimedia data on display 1316. Examples ofdisplay 1316 may include a light crystal display (LCD) panel, a plasmadisplay panel, a field emission display and the like.

In an embodiment the integrated circuit 1302 may be an applicationprocessor chip. In an embodiment, the integrated circuit 1302 may be apart of general processor chip embedded within a multimedia system.Examples of the multimedia systems may include, but are not limited to,(1) multimedia devices, such as cellular phones, digital video camerasand digital camcorders; (2) data processing devices, such as personalcomputers, laptops and personal digital assistants; and (3) consumerelectronics, such as set top boxes, digital video disk (DVD) players andvideo network servers.

Without in any way limiting the scope, interpretation, or application ofthe claims appearing below, advantages of one or more of the exemplaryembodiments disclosed herein include providing a masking of multimediadata without any additional hardware, as well as enabling theimplementation of complex computations to be avoided. For example,various embodiments provide privacy masking methods and systems that aretightly coupled with the logic of the multimedia encoder and do notdepend on external processing to achieve a degree of masking. Saidtechniques have a unique advantage in that they may be used in existingdevices/solutions which were not originally designed to enable privacymasking.

Another advantage of the disclosed methods for masking is that anadditional data load from the DDR to either subtract or overwrite themasked region may be avoided. The DMA data throughput that is to berealized remains the same as in the normal encoding flow. Accordingly,there is no impact on the DMA bandwidth. Additionally, for theimplementation of the disclosed methods and systems, the implementationof additional internal and external memory, as compared to normalencoding flow, may be avoided. Moreover, since there is no need for anypreprocessing steps/hardware to mask the ROI, the overall systemintegration is simple. Furthermore, due to the minimal impact onperformance without an increase in DDR bandwidth, the cost of the systemis much less.

Although the present technology has been described with reference tospecific exemplary embodiments, it is noted that various modificationsand changes may be made to these embodiments without departing from thebroad spirit and scope of the present technology. For example, thevarious devices, modules, analyzers, generators, etc., described hereinmay be enabled and operated using hardware circuitry (e.g.,complementary metal oxide semiconductor (CMOS) based logic circuitry),firmware, software and/or any combination of hardware, firmware, and/orsoftware (e.g., embodied in a machine readable medium). For example, thevarious electrical structures and methods may be embodied usingtransistors, logic gates, and electrical circuits (e.g., applicationspecific integrated circuit (ASIC) circuitry and/or in Digital SignalProcessor (DSP) circuitry).

Particularly, the system 400 of FIG. 4, the prediction module 404, thequantization module 406, the entropy encoding module 408, the predictionmode determination module 410, the guard band determination module 412,the QP determination module 414, and the rate control module 416 of FIG.4 may be enabled using software and/or using transistors, logic gates,and electrical circuits (e.g., integrated circuit circuitry such as ASICcircuitry).

Embodiments of the present disclosure include one or more computerprograms stored or otherwise embodied on a computer-readable medium,wherein the computer programs are configured to cause a processor toperform one or more operations. A computer-readable medium storing,embodying, or encoded with a computer program, or similar language, maybe embodied as a tangible data storage device storing one or moresoftware programs that are configured to cause a processor to performone or more operations. Such operations may be, for example, any of thesteps or operations described herein. Additionally, a tangible datastorage device may be embodied as one or more volatile memory devices,one or more non-volatile memory devices, and/or a combination of one ormore volatile memory devices and non-volatile memory devices.

Also, techniques, devices, subsystems and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present technology.Other items shown or discussed as directly coupled or communicating witheach other may be coupled through some interface or device, such thatthe items may no longer be considered directly coupled with each otherbut may still be indirectly coupled and in communication, whetherelectrically, mechanically, or otherwise, with one another. Otherexamples of changes, substitutions, and alterations ascertainable by oneskilled in the art, upon studying the exemplary embodiments disclosedherein, may be made without departing from the spirit and scope of thepresent technology.

It should be noted that reference throughout this specification tofeatures, advantages, or similar language does not imply that all of thefeatures and advantages should be or are in any single embodiment.Rather, language referring to the features and advantages may beunderstood to mean that a specific feature, advantage, or characteristicdescribed in connection with an embodiment may be included in at leastone embodiment of the present technology. Thus, discussions of thefeatures and advantages, and similar language, throughout thisspecification may, but do not necessarily, refer to the same embodiment.

Various embodiments of the present disclosure, as discussed above, maybe practiced with steps and/or operations in a different order, and/orwith hardware elements in configurations which are different than thosewhich are disclosed. Therefore, although the technology has beendescribed based upon these exemplary embodiments, it is noted thatcertain modifications, variations, and alternative constructions may beapparent and well within the spirit and scope of the technology.

Although various exemplary embodiments of the present technology aredescribed herein in a language specific to structural features and/ormethodological acts, the subject matter defined in the appended claimsis not necessarily limited to the specific features or acts describedabove. Rather, the specific features and acts described above aredisclosed as exemplary forms of implementing the claims.

The invention claimed is:
 1. A method, comprising: receiving, by one ormore processors, a frame comprising a video block; and performing, bythe one or more processors, prediction on the video block, comprising:performing prediction, by the one or more processors, on the video blockusing a first prediction mode, to generate a predicted video block,thereby privacy masking the video block, in response to determining thatthe video block is included in a privacy mask region of the frame; andperforming prediction, by the one or more processors, on the video blockusing a second prediction mode, to generate the predicted video block,in response to determining that the video block is not included in theprivacy mask region of the frame, the second prediction mode beingdifferent than the first prediction mode.
 2. The method of claim 1,further comprising: determining a plurality of sum of absolutedifferences (SAD) values associated with a plurality of prediction modesthat includes the first prediction mode and the second prediction mode,wherein the first prediction mode corresponds to a first SAD value ofthe SAD values, and wherein the second prediction mode corresponds to asecond SAD value of the SAD values, the second SAD value being differentthan the first SAD value.
 3. The method of claim 1, wherein the firstprediction mode is a DC mode, and wherein the second prediction mode isa prediction mode that corresponds to a lowest sum of absolutedifferences (SAD) value.
 4. The method of claim 3, further comprising:determining at least one guard band in proximity to at least oneboundary portion of the privacy mask region.
 5. The method of claim 4,further comprising: performing prediction in the at least one guard bandconfigured at a right-side boundary portion of the privacy mask regionbased on a vertical intra-prediction mode; and performing prediction inthe at least one guard band configured at a bottom boundary portion ofthe privacy mask region based on a horizontal intra-prediction mode. 6.The method of claim 1, further comprising: generating a residual blockbased on the predicted video block; and performing a quantization of theresidual block based on a quantization parameter (QP) value, the QPvalue being variable such that varying the QP value controls a degree ofmasking of the privacy mask region.
 7. The method of claim 1, furthercomprising: rendering at least one corner pixel associated with areference frame grey; generating at least one padded portion in thereference frame, the at least one padded portion comprising at least onegrey corner portion generated by using the at least one corner pixel;and causing at least one motion vector to point towards the at least onegrey corner portion to render the privacy mask region grey.
 8. A devicecomprising: one or more processors; and a non-transitory computerreadable storage medium storing a program for execution by the one ormore processors, the program including instructions to: receive a framecomprising a video block; and perform prediction on the video block,comprising instructions to: perform prediction on the video block usinga first prediction mode, to generate a predicted video block, therebyprivacy masking the video block, in response to determining that thevideo block is included in a privacy mask region of the frame; andperform prediction on the video block using a second prediction mode, togenerate the predicted video block, in response to determining that thevideo block is not included in the privacy mask region of the frame, thesecond prediction mode being different than the first prediction mode.9. The device of claim 8, wherein the instructions further compriseinstructions to: determine a plurality of sum of absolute differences(SAD) values associated with a plurality of prediction modes thatincludes the first prediction mode and the second prediction mode,wherein the first prediction mode corresponds to a first SAD value ofthe SAD values, and wherein the second prediction mode corresponds to asecond SAD value of the SAD values, the second SAD value being differentthan the first SAD value.
 10. The device of claim 8, wherein the firstprediction mode is a DC mode, and wherein the second prediction mode isa prediction mode that corresponds to a lowest sum of absolutedifferences (SAD) value.
 11. The device of claim 10, wherein theinstructions further comprise instructions to: determine at least oneguard band in proximity to at least one boundary portion of the privacymask region.
 12. The device of claim 11, wherein the instructionsfurther comprise instructions to: intra-predict the video block; performprediction in the at least one guard band configured at a right-sideboundary portion of the privacy mask region based on a verticalprediction mode; and perform prediction in the at least one guard bandconfigured at a bottom boundary portion of the privacy mask region basedon a horizontal prediction mode.
 13. The device of claim 8, wherein theinstructions further comprise instructions to: generate a residual blockbased on the predicted video block; and perform a quantization of theresidual block based on a quantization parameter (QP) value, the QPvalue being variable such that varying the QP value controls a degree ofmasking of the privacy mask region.
 14. The device of claim 8, whereinthe instructions further comprise instructions to: render at least onecorner pixel associated with a reference frame grey; generate at leastone padded portion in the reference frame, the at least one paddedportion comprising at least one grey corner portion generated by usingthe at least one corner pixel; and cause at least one motion vector topoint towards the at least one grey corner portion to render the privacymask region grey.
 15. A non-transitory computer readable storage mediumstoring a program for execution by one or more processors, the programincluding instructions to: receive a frame comprising a video block; andperform prediction on the video block, comprising instructions to:perform prediction on the video block using a first prediction mode, togenerate a predicted video block, thereby privacy masking the videoblock, in response to determining that the video block is included in aprivacy mask region of the frame; and perform prediction on the videoblock using a second prediction mode, to generate the predicted videoblock, in response to determining that the video block is not includedin the privacy mask region of the frame, the second prediction modebeing different than the first prediction mode.
 16. The non-transitorycomputer readable storage medium of claim 15, wherein the instructionsfurther comprise instructions to: determine a plurality of sum ofabsolute differences (SAD) values associated with a plurality ofprediction modes that includes the first prediction mode and the secondprediction mode, wherein the first prediction mode corresponds to afirst SAD value of the SAD values, and wherein the second predictionmode corresponds to a second SAD value of the SAD values, the second SADvalue being different than the first SAD value.
 17. The non-transitorycomputer readable storage medium of claim 15, wherein the firstprediction mode is a DC mode, and wherein the second prediction mode isa prediction mode that corresponds to a lowest sum of absolutedifferences (SAD) value.
 18. The non-transitory computer readablestorage medium of claim 17, wherein the instructions further compriseinstructions to: determine at least one guard band in proximity to atleast one boundary portion of the privacy mask region.
 19. Thenon-transitory computer readable storage medium of claim 18, wherein theinstructions further comprise instructions to: intra-predict the videoblock; perform prediction in the at least one guard band configured at aright-side boundary portion of the privacy mask region based on avertical prediction mode; and perform prediction in the at least oneguard band configured at a bottom boundary portion of the privacy maskregion based on a horizontal prediction mode.
 20. The non-transitorycomputer readable storage medium of claim 15, wherein the instructionsfurther comprise instructions to: generate a residual block based on thepredicted video block; and perform a quantization of the residual blockbased on a quantization parameter (QP) value, the QP value beingvariable such that varying the QP value controls a degree of masking ofthe privacy mask region.